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AN ANÆSTHETIST LOOKS AT A BURNT CHILD
[JAN. 15, 1955
ORIGINAL ARTICLES AN ANÆSTHETIST LOOKS AT A BURNT CHILD
D. W. SHANNON M.B. Edin., F.F.A. R.C.S. CONSULTANT ANÆSTRETIST, ROYAL HOSPITAL FOR SICK
CHILDREN, EDINBURGH The surgical treatment depends on the sum of a host of indispensible contributions... The best results follow only when each member of a hospital team, doctors and nurses alike, carries out their allotted task punctually and perfectly" (Learmonth success
of
1940).
1 the treatment of few surgical conditions is this truth better demonstrated than in the care of a seriously burnt child. The prevention and the treatment of shock, the preparation of burnt surfaces for grafting, the outcome of these operations, the relief of pain from dressing, and the maintenance of metabolic requirements depend not on techniques of a single individual but on the coordinated efforts of all members of a surgical team and the ability of each member to appreciate the problems of his
colleagues. The purpose of this paper is to review the position of the anaesthetist in such a team, to indicate his approach to the challenge, and to suggest possible approaches to meet the problems as they arise. Prevention and Treatment of
Oligaemic Shock of olig2emic shock, its
Nomatter what is the cause ultimate effect is anoxia. Recent work has shown that tissue anoxia converts shock from a reversible process to an irreversible state. Anoxia is also the most common cause of anaesthetic complications. Awareness of its likelihood, and its recognition and early treatment, are fundamental to good anaesthesia. It follows, therefore, that the anaesthetist is well equipped by training and experience to 2’lvise on the treatment of shock following burns. In addition to correction of the setiological factor the treatment of shock should be aimed at easing the burden on the vital systems by increasing the available oxygen supply, by improving its transport to the tissues, and by reducing the demand by the tissues. OXYGEN TRANSPORT
burn fluid is lost and red cells are destroyed in proportion to the extent and depth of the burn. These losses initiate shock, and correction by replacement of blood and fluid is urgent and imperative. There is a tendency to disparage the giving of whole blood and to favour the replacement of lost fluids with p!a.sma and plasma expanders alone ; yet in an extensive burn the resulting massive destruction of red cells and loss of haemoglobin reduce the total oxygen capacity of the circulating blood to dangerous levels and present an immediate grave prognosis, particularly in the young. The hemoglobin lost can be made good only by transfusion of whole blood. The use of whole blood, however, should not be confined to the extensive burn. Any burnt patient with healing delayed beyond three weeks has depressed marrow function with a low redAfter
a
table I—BURNS OF UP TO
6855
30%
cell count. If this secondary ansemia is allowed to persist, a metabolic disturbance is set up which has serious consequences to the patient. It must be treated by repeated blood-transfusions, which aim at maintaining a haemoglobin level of 80%. All patients with burns of more than 10% of their surface area require intravenous therapy to counter shock. The volume of fluid given must be carefully calculated if it is to be adequate and overloading of the circulation is to be avoided. Empirical assessment can never be satisfactorv even in expert hands. Various formulae are available. That introduced by Barclay and Wallace (1954) combines safety with effectiveness and simplicity. Their formula is based on the extent of the burn (fig. 1) in relation to the patient’s age (table i) and specifies the number of millilitres of plasma and electrolyte per 1% of body-surface burnt. The calculated total is divided into three equal parts, a third being given in the 8 hours immediately following the injury ; a third 8-24 hours after; and the remaining third 24-48 hours after.
Consider, for instance, a child, aged 18 months, admitted 2 hours after injury, with burns involving 20% of his body-surface. According Fig. I -"Rules of nine " for to table i the requirement estimating area of burn. is 15 ml. of plasma and 15 ml. of saline solution for each 1 % of body-surface burnt. Therefore 48 hours’ requirement for this child is 15 X 20 300 ml. of plasma + 300 ml. of saline solution. His requirement for the 8 hours immediately following the burn is 100 ml. + 100 ml., and this quantity must be given in the first 6 hours of treatment because he was admitted 2 hours after injury. =
Table i applies to burns of up to 30% of body-surface. For more extensive burns estimations from this table would lead to overloading of the circulation ; and volumes equivalent to 10% body-weight should be given
(table 11). It is important to remember that these amounts of fluid replace only the fluid lost as a result of the burn and are therefore termed " replacement fluids." A further adequate volume must be given to cover the normal metabolic fluid requirements of every child (table ill). Such volumes are termed " requirement fluids." Replacement fluid for patients with burns of less than 10% of the body-surface is given by mouth, and for patients with bilrns of more than 10% of the bodysurface intravenously.
OF BODY-SURFACE : PLASMA AND ELECTROLYTE EIGHT HOURS, AT DIFFERENT AGES
REQUIREMENTS
IN FIRST
FORTY-
112 TABLE H—BURNS
30%
OF OVER
OF BODY-SURFACE : AVERAGE WEIGHT AT DIFFERENT IN FIRST FORTY-EIGHT HOURS IS CALCULATED
AGES,
FROM WHICH FLUID
REQUIREMENT
TABLE
III-FLUID
INTAKE
(AS
GLUCOSE
DRINKS
OR
WATER) REQUIRED
TO
COVER
NORMAL
DAILY
METABOLIC
REQUIREMENTS
As already indicated, the restoration of circulating blood volume is of little value if its oxygen-carrying capacity (haemoglobin) remains deficient. In all patients with deep burns, and in all patients with extensive superficial burns involving more than 25% of the bodysurface, where the destruction of red cells has been considerable, half the total intravenous replacement fluid should be given as whole fresh blood, the other half being given as equal parts of saline solution and
plasma. In addition to replacement fluids, metabolic requirement fluids are given by mouth hourly unless the patient cannot retain oral fluid, as in gastric stasis and burns of the mouth, when it is also given intravenously as 5% dextrose in water. OXYGEN SUPPLY
The urgent need for fluid replacement must not blind the clinician to the fact that anoxia, although initiated in burn cases by a decrease in the oxygen-carrying capacity of the blood, is maintained and indeed exaggerated by other factors which, although not serious in themselves, may either in association with blood-loss or through their cumulative effect jeopardise the patient’s recovery. Clinical anoxia cannot be classifiedinto the compact compartments defined by Barcroft. Oxygenation of the tissues depends on the integrity of several interdependent systems (fig. 2), impairment of any one of which must necessarily affect all. Each system must be carefully checked, if irreversible damage from anoxia is to be prevented. The lungs are the reservoir from which the In the period immediately blood draws its oxygen. a blood and fluid are to be replaced, when burn, following it is important-perhaps vital-that the tension and volume of oxygen in the lungs be maintained at optimal levels. This depends on a clear airway and minute pulmonary ventilation.
Thick viscid
postnasal secretions ooze down into the laryngeal region and cause exhaustive bouts of coughing and intensify respiratory embarrassment. Some time ago a child in this unit died from asphyxiation due to a mucous crust blocking the laryngeal aperture. The cause of this sudden unexpected death was not appreciated until necropsy. Without doubt the
nurses
must
give the same scrupulous attention to oral and nasal hygiene as to the care of the burnt surface. Other simple happenings, innocent in themselves, are often overlooked. Lolling of the child’s head on the pillow may lead to obstruction of the airway, particularly if the tonsils and adenoids are enlarged. In such a child, if the airway cannot be maintained by simple procedures, a nasopharyngeal airway lubricated with an analgesic (2% cinchocaine) ointment should be passed. Again, if the circulation is overloaded by excessive replacement of fluids, a transudate fills the alveolar spaces and interferes with the diffusion of oxygen across the alveolar-capillary membrane. This danger is enhanced by the primitive and uncertain method (external pressure on rubber tubing) by which the flow of fluids into the patient is apt to be encouraged. It is a complication that readily occurs in young children with their small circulat-
Airway This can readily become obstructed. The breathing of hot irritating fumes may cause laryngeal cedema or lead to the accumulation of desquamated cells and mucopurulent secretions in the tracheobronchial tree. The patient will be eyanosed and will struggle for breath. The need for clearing the airway is imperative, and treatment
by tracheotomy
or
by bronchoscopic aspiration over the replace-
will, where necessary, take precedence ment of fluids.
Less dramatic. causes of respiratory embarrassment may tend to pass unnoticed, but their very persistence in a shocked patient can delay recovery and may on occasion eventually endanger life. Crusting of secretions within the nasal vestibules is common not only in burns involving the face but also in any dehydrated child. It forces mouth-breathing with all its barmful effects.
Fig. 2-Factors responsible for oxygenation of tissues.
113 too little be achieved only by careful and continued supervision of the drip. Too often this supervision is left to the nurses, who lack the experience and basic knowledge which the safety of the child demands ; and furthermore it is not their responsibility.
ing blood volume. The compromise between and too much
TABLE
IV-DOSAGE
can
ltiiiitte Pzc2izonary Ventilation The tension and the volume of oxygen in the lungs depend on the summation of the rate and, depth of breathing. This depends on the integrity of the respiratory centre, and the efficiency of the respiratory muscles. After a burn there is central stimulation due to pain and fear. The rate of breathing is increased without a proportionate increase in the depth. This rapid shallow breathing is particularly common in children with burns involving the chest and abdomen. By the relative increase in the dead air volume and the speed at which air is being drawn through the narrow tracheobronchial tree this type of breathing is inefficient, obstructive, and exhausting to the child. The child must be given relief through the careful administration of opiates. Further precautions must be taken to ensure that the harmful effects are not exaggerated by the application of heavy blankets or constricting bandages, and that the high Trendelenburg position does not interfere with free intercostal and
diaphragmatic movements. Opinions differ about the
value of oxygen in the treatment of shock. The claims for oxygen therapy, however, can never be dismissed lightly, since time and again in the course of one’s duties its undoubted value has been experienced. In this unit oxygen is given routinely to children with burns involving more than 30% of the bodysurface, and to any child in whom there is evidence of a reduction in the pulmonary ventilation and of peripheral
must be
TABLE
OF PREOPERATIVE OPERATIVE DRUGS
given to the handling anxiety-restlessness. Handling of the Patient
of the
patient
AND
POST-
and to the
control of
This must be reduced to a minimum, only essential diagnostic and therapeutic measures being permitted. These measures must be taken with speed and precision by doctors and nurses versed in their intricacies. Skill and experience are required in feeding and in setting up blood-transfusion apparatus for a young child. These important measures cannot be left to an inexperienced nurse or houseman, who may labour for an hour or more, exhausting the child and themselves before calling for assistance. and Restlessness These must be relieved. Care must be taken, however, before administering depressant drugs that restlessness is an evidence of pain and not visible evidence of the patient’s fight to relieve tissue anoxia. Sedative drugs must be used circumspectly, and their effect on the rate and depth of breathing must be carefully observed. Diamorphine hydrochloride is our drug of choice for children and is given, on admission, in doses based on the age (table iv), half the dose being given subcutaneously and half intravenously. The dose may be repeated 4-hourly.
Anxiety
failure. High concentrations of oxygen increase the volume and tension of oxygen in the pulmonary alveoli and, used as a therapeutic adjuvant, tide the hydrochloride may seem an unusual drug patient over a period of acute anoxia while efforts are to Diamorphine select. It has been used routinely in this hospital for many made to the in the correct being deficiency circulating- years as a postoperative sedative, and it was a natural choice blood volume. Its value depends on a clear airway in burnt children. The reputed respiratory depressant effect (oxygen can neither correct nor surmount an obstructive of diamorphine hydrochloride, however, with the threat of barrier) and the care with which the apparatus is con- anoxia encouraged investigation of the potentialities of nected and maintained. Too often one sees the oxygen morphine and the barbiturates. Neither gave satisfaction. cylinder, with its connections carelessly fitted, fizzing Idiosyncrasy to morphine is not uncommon in children, making it unsuitable for routine use, and its respiratory away uselessly ; or the thin rubber tubing conducting depressant effect appeared more pronounced than that of oxygen to the patient may be kinked as it leaves the The barbiturates (quinaldiamorphine hydrochloride. the bed-head ; or a perished barbitone cylinder and arches over sodium and phenobarbitone), as might be expected, with harness is nose-piece, inaccurately adjusted, excited rather than depressed the child in pain, and their collapsed and twisted and obstructs the patient’s airway. repeated administration exerted a cumulative effect with Worst of all, the humidifier may be incorrectly fitted, prolonged and undesirable drowsiness. when water will be siphoned into the lungs. On occasion a seriously burnt child has received an Oxygen is best given to children through an intra- overdose of opiate before admission. An infant, aged 3 nasal catheter with several holes in its terminal inch to to this unit had been given gr. 1/8 of admitted weeks, disperse the gas and to prevent the gas from impinging ventilation volume, in such The morphine. pulmonary constantly against one spot. The tube should be a a dangerous level, and it be reduced to case, may lubricated with analgesic ointment and strapped over may be necessary to assist the child’s breathing. Oxygen the nasal bridge and forehead, leaving sufficient slack is given through an endotracheal tube, if necessary, by to allow free movement of the child’s head. manual compression of the rebreathing bag Oxygen is delivered through a humidifier at a flow- rhythmic of an anaesthetic machine, until the patient can actively rate of 2-3 litres a minute, and once every 12 hours the tube must be removed and replaced through the alternate maintain adequate ventilation. nostril. Pre-anaesthetic Assessment Only if attention is given to every detail can one be The general disturbances effecting and resulting from certain that oxygen’ is being given as a therapeutic oligaemic shock having been corrected and brought under measure and not as a therapeutic gesture. control, consideration must next be given to the local OXYGEN DEMAND treatment of the burn. This treatment varies from the application of a simple dressing to extensive cleansing If the post-war years have taught anything, it is that and grafting. It therefore becomes necessary to assess when goods are scarce one must economise in their use. The simple economic law might be applied with advan- the capacity of the patient to meet these operations. Táge to the treatment of shock. In this state, as has been If this assessment is to be made with any degree of íulieatefl, interference with the transport of oxygen accuracy, the ansesthetist must be aware of the following factors: re-tricts its supply to the tissues, and the demands of the ti4nes must be reduced accordingly. Consideration (1) The clinical state of the patient.
circulatory
114
(2) The nature of the operation, its benefits to the patient, and the metabolic and physiological disturbances associated with it. (3) The hazards of the particular anaesthetic technique required to provide satisfactory operating conditions for the surgeon. (-t) The capability or, possibly more important, the limitations of the surgeon and the anaesthetist. Just as the preparation of a burnt child is directed towards easing the burden on the respiratory and cardiovascular systems, so the assessment of the burnt child depends on the functional efficiency of these systems. This assessment can be made only on clinical grounds. Special investigations and reports by non-clinical departments, although informative in a later review of the case, are necessarily delayed and often confusing, and their importance tends to be overemphasised. The seriously burnt patient cannot be assessed from a single clinical examination, since the response of a shocked child, and the manner of his response, to restorative measures and replacement therapy can vary from hour to hour. The clinician should rely on frequent bedside observations : the colour of the skin and mucosae, the temperature of the skin, the feel of the pulse, the capillary-filling time, the rate and rhythm of breathing, and the dryness of the tongue and lips-attempting by experience to acquire something of the clinical perception of the physicians of
yesteryear. The clinician anaesthetist accompanies the surgeon on his repeated visits from the time of the child’s admission to hospital, and from observations must be prepared to discuss, at any time, the advantages or dangers to the patient of whatever operation the surgeon may consider advisable. The early local treatment of burns-cleansing and the application of dressings-presents few problems to the anaesthetist. The immediate threat of shock has been relieved, and these operations can be done under diamorphine hydrochloride, or the patient can be given low concentrations of cyclopropane, the gas being used as a form of controlled sedation. Later, usually between the 10th and 14th days after a burn, sloughs begin to separate, and a decision must be made about the best time for excising the eschar, whether extensive excision and grafting of the raw surfaces should be done, or whether the burnt area should be treated piecemeal. After extensive deep burns the patient’s condition may begin to deteriorate between the 7th and 10th days. The child becomes fevered and chesty, with a rapid pulse, or, as has happened in three cases in this unit, becomes hypopyrexial, disoriented, and later comatose. It is just such patients, however, who benefit most from heroic, rather than conservative, measures. The anaesthetist must be sufficientlv informed on the benefits of this action to advise the surgeon on the child’s ability to stand the stress of extensive surgery, and whether the anticipated blood-loss can be replaced by immediate blood-transfusion or prevented by using a
hypotensive drug.
referring seriously ill patients to for preoperative assessment is to be deplored. physicians Any member of a surgical team should be better equipped to advise than a physician, who is ill-informed on many of the essential physiopathological upsets. The custom is less common than it was ; but physicians, from time The
custom
disregard for
enviable the hazards of as their considered opinion that a seriously burnt child will survivean operation of uncertain nature, providing a non-toxic agent, such as nitrous oxide, is used. I submit that the anaesthetist to the surgical team is best equipped to advise on the resultant of the four He is familiar with the variables mentioned above. hazards of anesthesia. His training has taught him to
to
time, with
of
an
anaesthesia, record
appreciate the effects on the patient of blood-loss and I surgical trauma associated with particular operations. I He knows, none better, the capabilities of his surgeon. I .
Pre-anoesthetic Medication is Atropine given to all patients in a dose proportional to the age of the patient. Children tolerate relatively large amounts of atropine and rarely show the uncomfortable-looking buccal and labial mucosa so characteristic of the atropinised adult. In the weeks immediately following a severe burn repeated anaesthetics are necessary to permit dressings and grafting operations. During this period too the basal metabolic rate rises rapidly and may remain
dry
t
raised for several months. This necessitates a nutritional intake well above normal requirements, and from the 2nd day onwards it is the custom, in this unit, for children to be put on a carefully planned diet. Recovery from anaesthesia must be rapid and uncomplicated if inter. ference with this dietetic regime is to be avoided. The anaesthetist should aim at having the child awake within minutes of completion of the dressing or operation, so that food may be given within an hour or two of his leaving the operating-theatre. For this reason pre. operative sedation is rarely used. This is contrary to the expressed opinion of psychiatrists, but experience has given little support to their anxious forebodings. Despite, or possibly because of, repeated anaesthetic experiences the child is surprisingly cooperative, appears to welcome the frequent visits to the theatre, and, with the anaesthetic technique detailed below, goes to sleep rapidly and
quietly. The occasional child who refused to become emotionally reconciled to visiting the theatre is given barbitone sodium by mouth (for dosage see table iv). This drug usually puts the patient to sleep and, because of the rate at which it is metabolised, recovery from its effects is fairly rapid. Should an operation be necessary in the period immediately following a burn, the child is controlled with diamorphine hydrochloride. At this time metabolic requirements are satisfied by parenteral administration. The haemoglobin level must be estimated preoperatively and any anaemia corrected. For grafting operations, during which the removal of skin and the excision of granulations will cause blood-loss, it is essential that a blood-transfusion should be given in the immediate preoperative period and again during the operation to replace any loss.
quinaÌ.
Anaesthetic
Technique
Once upon a time an inspired surgeon must have attributed the unfortunate death of one of his patients to his (the patient’s) failure to stand the anaesthetic." Since then this aphorism has been to the surgeon what enlargement of the thymus has been to the anaesthetist, and a surgeon, before subjecting a seriously ill patient to a lengthy and hazardous surgical operation, is often heard to ask the anaesthetist to examine the patient and report on his fitness to stand the anaesthetic." A review of the literature on anaesthesia, however. would almost certainly show that it is not the seriously ill patient who is likely to die from an anaesthetic but the robust healthy child who has been badly prepared. Furtber investigation would show that these deaths could invariably be attributed to some avoidable indiscretion on the part of the anaesthetist. The seriously ill patient appears to be unusually resistant to the hazards of anaesthesia and occasionally appears to be in better condition after the operation than he was before. This paradox is explained by the fact that the seriously ill are normally anaesthetised by experienced anaesthetists. Thev are less resistant to the effects of anaesthetic:. and satisfactory operating conditions may be induced "
"
115 ul maintained with relatively small amounts of anae.sftittit. In addition, modern anaesthetic techniques, far from being a danger to the patient, embrace the essentials of resuscitative therapy : rest, positioning, gen. blood-transfusions, &c. ruder anesthesia the patient is at complete rest ; :he airway is carefully maintained ;oxygen is given in high concentration and with positive pressure if necessary; rate and depth of breathing are maintained at optimal level : the pulse, colour, and blood-pressure are continuallyobserved and their significance interpreted ; where necessary to replace loss during bloud ,-neusive grafting operations, and the rate of the transfusion is regulated to satisfy the immediate needs of the patient. The seriously burnt child, to whom these restorative measures are so vitally important, shows benefit from this concentrated attention and, providing the surgical operanon is completed without unnecessary surgical trauma, appears in better clinical condition after the operation.
’ TABLE
agent
1) A rapid smooth induction free from coughing, struggling, which exhaust the child and stimulate the of obstructive secretions. (2) A high concentration of oxygen to satisfy the theranrutic and increased metabolic demands of the burnt child.
crying,
formation
3 Quiet breathing. (4) Minimal disturbance of metabolic and physiological" tumetions. The
surgical team has already spent many hours correct the upset caused by the burn. recovery to allow full and early expansion of the
attempting to (5) Rapid mgs
and
rapid resumption
of the dietetic
regime.
cyclopropane is well suited to meet these demands of the child. It may be given with high concentrations of and, being excreted unchanged, produces minimal of the body chemistry. Its central depressant ensures quiet breathing ; but most important is it is a gas. Absorbed and expelled through the lungs allows the anaesthetist to control not only its administon but also itsexcretion. This, combined with the . That cyclopropane is a powerful non-irritant agent a child from consciousness to respiramable of - arrest in 60-75 seconds, makes it the most flexible controllable of permitting rapid smooth tion. easy maintenance, and return to consciousness leavingthe operating-table. Feeding may be med 2-3 hours later. of Administration dopropane is administered with circle absorption the very young (aged less than 3 years), with a
taking
’
agents,
’
absorption.
DIMENSIONS
OF
MAGILL
,
It is impossible to dogmatise on the best anaesthetic agent for a burnt child. Indeed the flood of literature emanating from different centres and extolling the virtues of particular drugs for similar operations must lie very confusing to the casual anaesthetist and neutral observer. The truth is that the patient’s safety does not depend on the pharmacology of an anaesthetic drug so much as on the skill and experience of the anaesthetist administering it, combined with careful preparation and the meticulous application of whatever anaesthetic technique. is decided on. Anæthetic drugs are used essentially to provide satisfactory operating conditions, which, in similar operations, vary with individual surgeons. One may be able to work competently with a lightly anaesthetised patient where another would require, and demand, the curarised, pulseless, apnoeic, anthropomorphous mass popularised by the modern anaesthetist. Fortunately, in burns, the requirements of the surgeon are few. All he asks is a quiet patient and access to the burnt areas. It is possible, therefore, for the anaesthetist ti, concentrate on the demands of the child. These are as follows: - tnd
TUBES :
ORAL TUBES
is given
Anasthetic
V—ENDOTRACHEAL
Rapid induction to surgical anaesthesia is achieved after five or six breaths (30-40 seconds) by giving high concentrations of cyclopropane, the proportion of cyclopropane to oxygen being 3 to 1, and an2esthesia is maintained with a flow-rate of cyclopropane : oxygen 1 : 3 (50-100 c.cm. of cyclopropane : 300 c.cm. of oxygen). When the dressing is applied, the cyclopropane is turned off, and after one or two breaths of oxygen the mask is removed. Endotracheal intubation is used as an aid to the administration of cyclopropane in the following conditions : (1) Burns involving the face, head, and neck, if the surgeon is to have reasonable access to the parts. (2) Burns involving the dorsal surfaces, when positioning the child makes it difficult to maintain a clear airway. (3) Any child in whom respiratory embarrassment, even though minor, persists and cannot be relieved by either manipulation or the use of an oral airway. -
-
It has been suggested that the introduction of an endotracheal tube narrows the already narrow trachea of a child to a degree which itself causes respiratory embarrassment. This premise stimulated the corollary that the largest possible tube should be used and has led anaesthetists to screwing " into the trachea uncomfortably large lubricated tubes. I believe, despite assertions to the contrary, that it is the maintained pressure from such tubes that initiates the formation of membranes and post-anæsthetic laryngeal oedema reported recently. The tube sizes detailed in table v are proportionate to the size of the child ; they ensure an undisturbed airway and lie comfortably within the larynx. With such tubes these dangerous complications do not develop. Gentle handling is necessary in introducing the tube, particularly in the ill-nourished child with infection of the oropharynx ; but, provided the tube is introduced atraumatically, I have not found that these factors predispose to laryngeal oedema. It is unnecessary to lubricate the tube. Even although atropine has been given, the slimy moistness of the child’s laryngeal mucosa allows it to slip easily and atraumatically into the larynx. In children aged less than 8 years the vocal cords appear to mould themselves round the tube, and an airtight fit is obtained without a pharyngeal pack. This anaesthetic technique has been used routinely during the past eight years to anaesthetise children with burnt areas ranging from a slight extent to 60-70% of the body-surface. The results have been most satisfactory. The only complication during administration has been an occasional bronchospasm, which may be dangerous if not recognised early and rapidly relieved by the application of steady manual pressure to the rebreathing bag filled with oxygen. Cardiac irregularities associated with the use of cyclopropane in adults are rarely observed, and there have been no cases of postoperative atelectasis. "
I wish to thank Mr. A. B. Wallace, F.R.C.S.E., for encouragement and help in writing this article. REFERENCES
Barclay,
T.
L., Wallace, A. B. (1954) Lancet, i,
98.
Learmonth, J. R. (1940) In War-time Nurse. Edited by J. M. Mackintosh. Edinburgh; chapter III.
ORIGINAL ARTICLES AN ANÆSTHETIST LOOKS AT A BURNT CHILD
D. W. SHANNON M.B. Edin., F.F.A. R.C.S. CONSULTANT ANÆSTRETIST, ROYAL HOSPITAL FOR SICK
CHILDREN, EDINBURGH The surgical treatment depends on the sum of a host of indispensible contributions... The best results follow only when each member of a hospital team, doctors and nurses alike, carries out their allotted task punctually and perfectly" (Learmonth success
of
1940).
1 the treatment of few surgical conditions is this truth better demonstrated than in the care of a seriously burnt child. The prevention and the treatment of shock, the preparation of burnt surfaces for grafting, the outcome of these operations, the relief of pain from dressing, and the maintenance of metabolic requirements depend not on techniques of a single individual but on the coordinated efforts of all members of a surgical team and the ability of each member to appreciate the problems of his
colleagues. The purpose of this paper is to review the position of the anaesthetist in such a team, to indicate his approach to the challenge, and to suggest possible approaches to meet the problems as they arise. Prevention and Treatment of
Oligaemic Shock of olig2emic shock, its
Nomatter what is the cause ultimate effect is anoxia. Recent work has shown that tissue anoxia converts shock from a reversible process to an irreversible state. Anoxia is also the most common cause of anaesthetic complications. Awareness of its likelihood, and its recognition and early treatment, are fundamental to good anaesthesia. It follows, therefore, that the anaesthetist is well equipped by training and experience to 2’lvise on the treatment of shock following burns. In addition to correction of the setiological factor the treatment of shock should be aimed at easing the burden on the vital systems by increasing the available oxygen supply, by improving its transport to the tissues, and by reducing the demand by the tissues. OXYGEN TRANSPORT
burn fluid is lost and red cells are destroyed in proportion to the extent and depth of the burn. These losses initiate shock, and correction by replacement of blood and fluid is urgent and imperative. There is a tendency to disparage the giving of whole blood and to favour the replacement of lost fluids with p!a.sma and plasma expanders alone ; yet in an extensive burn the resulting massive destruction of red cells and loss of haemoglobin reduce the total oxygen capacity of the circulating blood to dangerous levels and present an immediate grave prognosis, particularly in the young. The hemoglobin lost can be made good only by transfusion of whole blood. The use of whole blood, however, should not be confined to the extensive burn. Any burnt patient with healing delayed beyond three weeks has depressed marrow function with a low redAfter
a
table I—BURNS OF UP TO
6855
30%
cell count. If this secondary ansemia is allowed to persist, a metabolic disturbance is set up which has serious consequences to the patient. It must be treated by repeated blood-transfusions, which aim at maintaining a haemoglobin level of 80%. All patients with burns of more than 10% of their surface area require intravenous therapy to counter shock. The volume of fluid given must be carefully calculated if it is to be adequate and overloading of the circulation is to be avoided. Empirical assessment can never be satisfactorv even in expert hands. Various formulae are available. That introduced by Barclay and Wallace (1954) combines safety with effectiveness and simplicity. Their formula is based on the extent of the burn (fig. 1) in relation to the patient’s age (table i) and specifies the number of millilitres of plasma and electrolyte per 1% of body-surface burnt. The calculated total is divided into three equal parts, a third being given in the 8 hours immediately following the injury ; a third 8-24 hours after; and the remaining third 24-48 hours after.
Consider, for instance, a child, aged 18 months, admitted 2 hours after injury, with burns involving 20% of his body-surface. According Fig. I -"Rules of nine " for to table i the requirement estimating area of burn. is 15 ml. of plasma and 15 ml. of saline solution for each 1 % of body-surface burnt. Therefore 48 hours’ requirement for this child is 15 X 20 300 ml. of plasma + 300 ml. of saline solution. His requirement for the 8 hours immediately following the burn is 100 ml. + 100 ml., and this quantity must be given in the first 6 hours of treatment because he was admitted 2 hours after injury. =
Table i applies to burns of up to 30% of body-surface. For more extensive burns estimations from this table would lead to overloading of the circulation ; and volumes equivalent to 10% body-weight should be given
(table 11). It is important to remember that these amounts of fluid replace only the fluid lost as a result of the burn and are therefore termed " replacement fluids." A further adequate volume must be given to cover the normal metabolic fluid requirements of every child (table ill). Such volumes are termed " requirement fluids." Replacement fluid for patients with burns of less than 10% of the body-surface is given by mouth, and for patients with bilrns of more than 10% of the bodysurface intravenously.
OF BODY-SURFACE : PLASMA AND ELECTROLYTE EIGHT HOURS, AT DIFFERENT AGES
REQUIREMENTS
IN FIRST
FORTY-
112 TABLE H—BURNS
30%
OF OVER
OF BODY-SURFACE : AVERAGE WEIGHT AT DIFFERENT IN FIRST FORTY-EIGHT HOURS IS CALCULATED
AGES,
FROM WHICH FLUID
REQUIREMENT
TABLE
III-FLUID
INTAKE
(AS
GLUCOSE
DRINKS
OR
WATER) REQUIRED
TO
COVER
NORMAL
DAILY
METABOLIC
REQUIREMENTS
As already indicated, the restoration of circulating blood volume is of little value if its oxygen-carrying capacity (haemoglobin) remains deficient. In all patients with deep burns, and in all patients with extensive superficial burns involving more than 25% of the bodysurface, where the destruction of red cells has been considerable, half the total intravenous replacement fluid should be given as whole fresh blood, the other half being given as equal parts of saline solution and
plasma. In addition to replacement fluids, metabolic requirement fluids are given by mouth hourly unless the patient cannot retain oral fluid, as in gastric stasis and burns of the mouth, when it is also given intravenously as 5% dextrose in water. OXYGEN SUPPLY
The urgent need for fluid replacement must not blind the clinician to the fact that anoxia, although initiated in burn cases by a decrease in the oxygen-carrying capacity of the blood, is maintained and indeed exaggerated by other factors which, although not serious in themselves, may either in association with blood-loss or through their cumulative effect jeopardise the patient’s recovery. Clinical anoxia cannot be classifiedinto the compact compartments defined by Barcroft. Oxygenation of the tissues depends on the integrity of several interdependent systems (fig. 2), impairment of any one of which must necessarily affect all. Each system must be carefully checked, if irreversible damage from anoxia is to be prevented. The lungs are the reservoir from which the In the period immediately blood draws its oxygen. a blood and fluid are to be replaced, when burn, following it is important-perhaps vital-that the tension and volume of oxygen in the lungs be maintained at optimal levels. This depends on a clear airway and minute pulmonary ventilation.
Thick viscid
postnasal secretions ooze down into the laryngeal region and cause exhaustive bouts of coughing and intensify respiratory embarrassment. Some time ago a child in this unit died from asphyxiation due to a mucous crust blocking the laryngeal aperture. The cause of this sudden unexpected death was not appreciated until necropsy. Without doubt the
nurses
must
give the same scrupulous attention to oral and nasal hygiene as to the care of the burnt surface. Other simple happenings, innocent in themselves, are often overlooked. Lolling of the child’s head on the pillow may lead to obstruction of the airway, particularly if the tonsils and adenoids are enlarged. In such a child, if the airway cannot be maintained by simple procedures, a nasopharyngeal airway lubricated with an analgesic (2% cinchocaine) ointment should be passed. Again, if the circulation is overloaded by excessive replacement of fluids, a transudate fills the alveolar spaces and interferes with the diffusion of oxygen across the alveolar-capillary membrane. This danger is enhanced by the primitive and uncertain method (external pressure on rubber tubing) by which the flow of fluids into the patient is apt to be encouraged. It is a complication that readily occurs in young children with their small circulat-
Airway This can readily become obstructed. The breathing of hot irritating fumes may cause laryngeal cedema or lead to the accumulation of desquamated cells and mucopurulent secretions in the tracheobronchial tree. The patient will be eyanosed and will struggle for breath. The need for clearing the airway is imperative, and treatment
by tracheotomy
or
by bronchoscopic aspiration over the replace-
will, where necessary, take precedence ment of fluids.
Less dramatic. causes of respiratory embarrassment may tend to pass unnoticed, but their very persistence in a shocked patient can delay recovery and may on occasion eventually endanger life. Crusting of secretions within the nasal vestibules is common not only in burns involving the face but also in any dehydrated child. It forces mouth-breathing with all its barmful effects.
Fig. 2-Factors responsible for oxygenation of tissues.
113 too little be achieved only by careful and continued supervision of the drip. Too often this supervision is left to the nurses, who lack the experience and basic knowledge which the safety of the child demands ; and furthermore it is not their responsibility.
ing blood volume. The compromise between and too much
TABLE
IV-DOSAGE
can
ltiiiitte Pzc2izonary Ventilation The tension and the volume of oxygen in the lungs depend on the summation of the rate and, depth of breathing. This depends on the integrity of the respiratory centre, and the efficiency of the respiratory muscles. After a burn there is central stimulation due to pain and fear. The rate of breathing is increased without a proportionate increase in the depth. This rapid shallow breathing is particularly common in children with burns involving the chest and abdomen. By the relative increase in the dead air volume and the speed at which air is being drawn through the narrow tracheobronchial tree this type of breathing is inefficient, obstructive, and exhausting to the child. The child must be given relief through the careful administration of opiates. Further precautions must be taken to ensure that the harmful effects are not exaggerated by the application of heavy blankets or constricting bandages, and that the high Trendelenburg position does not interfere with free intercostal and
diaphragmatic movements. Opinions differ about the
value of oxygen in the treatment of shock. The claims for oxygen therapy, however, can never be dismissed lightly, since time and again in the course of one’s duties its undoubted value has been experienced. In this unit oxygen is given routinely to children with burns involving more than 30% of the bodysurface, and to any child in whom there is evidence of a reduction in the pulmonary ventilation and of peripheral
must be
TABLE
OF PREOPERATIVE OPERATIVE DRUGS
given to the handling anxiety-restlessness. Handling of the Patient
of the
patient
AND
POST-
and to the
control of
This must be reduced to a minimum, only essential diagnostic and therapeutic measures being permitted. These measures must be taken with speed and precision by doctors and nurses versed in their intricacies. Skill and experience are required in feeding and in setting up blood-transfusion apparatus for a young child. These important measures cannot be left to an inexperienced nurse or houseman, who may labour for an hour or more, exhausting the child and themselves before calling for assistance. and Restlessness These must be relieved. Care must be taken, however, before administering depressant drugs that restlessness is an evidence of pain and not visible evidence of the patient’s fight to relieve tissue anoxia. Sedative drugs must be used circumspectly, and their effect on the rate and depth of breathing must be carefully observed. Diamorphine hydrochloride is our drug of choice for children and is given, on admission, in doses based on the age (table iv), half the dose being given subcutaneously and half intravenously. The dose may be repeated 4-hourly.
Anxiety
failure. High concentrations of oxygen increase the volume and tension of oxygen in the pulmonary alveoli and, used as a therapeutic adjuvant, tide the hydrochloride may seem an unusual drug patient over a period of acute anoxia while efforts are to Diamorphine select. It has been used routinely in this hospital for many made to the in the correct being deficiency circulating- years as a postoperative sedative, and it was a natural choice blood volume. Its value depends on a clear airway in burnt children. The reputed respiratory depressant effect (oxygen can neither correct nor surmount an obstructive of diamorphine hydrochloride, however, with the threat of barrier) and the care with which the apparatus is con- anoxia encouraged investigation of the potentialities of nected and maintained. Too often one sees the oxygen morphine and the barbiturates. Neither gave satisfaction. cylinder, with its connections carelessly fitted, fizzing Idiosyncrasy to morphine is not uncommon in children, making it unsuitable for routine use, and its respiratory away uselessly ; or the thin rubber tubing conducting depressant effect appeared more pronounced than that of oxygen to the patient may be kinked as it leaves the The barbiturates (quinaldiamorphine hydrochloride. the bed-head ; or a perished barbitone cylinder and arches over sodium and phenobarbitone), as might be expected, with harness is nose-piece, inaccurately adjusted, excited rather than depressed the child in pain, and their collapsed and twisted and obstructs the patient’s airway. repeated administration exerted a cumulative effect with Worst of all, the humidifier may be incorrectly fitted, prolonged and undesirable drowsiness. when water will be siphoned into the lungs. On occasion a seriously burnt child has received an Oxygen is best given to children through an intra- overdose of opiate before admission. An infant, aged 3 nasal catheter with several holes in its terminal inch to to this unit had been given gr. 1/8 of admitted weeks, disperse the gas and to prevent the gas from impinging ventilation volume, in such The morphine. pulmonary constantly against one spot. The tube should be a a dangerous level, and it be reduced to case, may lubricated with analgesic ointment and strapped over may be necessary to assist the child’s breathing. Oxygen the nasal bridge and forehead, leaving sufficient slack is given through an endotracheal tube, if necessary, by to allow free movement of the child’s head. manual compression of the rebreathing bag Oxygen is delivered through a humidifier at a flow- rhythmic of an anaesthetic machine, until the patient can actively rate of 2-3 litres a minute, and once every 12 hours the tube must be removed and replaced through the alternate maintain adequate ventilation. nostril. Pre-anaesthetic Assessment Only if attention is given to every detail can one be The general disturbances effecting and resulting from certain that oxygen’ is being given as a therapeutic oligaemic shock having been corrected and brought under measure and not as a therapeutic gesture. control, consideration must next be given to the local OXYGEN DEMAND treatment of the burn. This treatment varies from the application of a simple dressing to extensive cleansing If the post-war years have taught anything, it is that and grafting. It therefore becomes necessary to assess when goods are scarce one must economise in their use. The simple economic law might be applied with advan- the capacity of the patient to meet these operations. Táge to the treatment of shock. In this state, as has been If this assessment is to be made with any degree of íulieatefl, interference with the transport of oxygen accuracy, the ansesthetist must be aware of the following factors: re-tricts its supply to the tissues, and the demands of the ti4nes must be reduced accordingly. Consideration (1) The clinical state of the patient.
circulatory
114
(2) The nature of the operation, its benefits to the patient, and the metabolic and physiological disturbances associated with it. (3) The hazards of the particular anaesthetic technique required to provide satisfactory operating conditions for the surgeon. (-t) The capability or, possibly more important, the limitations of the surgeon and the anaesthetist. Just as the preparation of a burnt child is directed towards easing the burden on the respiratory and cardiovascular systems, so the assessment of the burnt child depends on the functional efficiency of these systems. This assessment can be made only on clinical grounds. Special investigations and reports by non-clinical departments, although informative in a later review of the case, are necessarily delayed and often confusing, and their importance tends to be overemphasised. The seriously burnt patient cannot be assessed from a single clinical examination, since the response of a shocked child, and the manner of his response, to restorative measures and replacement therapy can vary from hour to hour. The clinician should rely on frequent bedside observations : the colour of the skin and mucosae, the temperature of the skin, the feel of the pulse, the capillary-filling time, the rate and rhythm of breathing, and the dryness of the tongue and lips-attempting by experience to acquire something of the clinical perception of the physicians of
yesteryear. The clinician anaesthetist accompanies the surgeon on his repeated visits from the time of the child’s admission to hospital, and from observations must be prepared to discuss, at any time, the advantages or dangers to the patient of whatever operation the surgeon may consider advisable. The early local treatment of burns-cleansing and the application of dressings-presents few problems to the anaesthetist. The immediate threat of shock has been relieved, and these operations can be done under diamorphine hydrochloride, or the patient can be given low concentrations of cyclopropane, the gas being used as a form of controlled sedation. Later, usually between the 10th and 14th days after a burn, sloughs begin to separate, and a decision must be made about the best time for excising the eschar, whether extensive excision and grafting of the raw surfaces should be done, or whether the burnt area should be treated piecemeal. After extensive deep burns the patient’s condition may begin to deteriorate between the 7th and 10th days. The child becomes fevered and chesty, with a rapid pulse, or, as has happened in three cases in this unit, becomes hypopyrexial, disoriented, and later comatose. It is just such patients, however, who benefit most from heroic, rather than conservative, measures. The anaesthetist must be sufficientlv informed on the benefits of this action to advise the surgeon on the child’s ability to stand the stress of extensive surgery, and whether the anticipated blood-loss can be replaced by immediate blood-transfusion or prevented by using a
hypotensive drug.
referring seriously ill patients to for preoperative assessment is to be deplored. physicians Any member of a surgical team should be better equipped to advise than a physician, who is ill-informed on many of the essential physiopathological upsets. The custom is less common than it was ; but physicians, from time The
custom
disregard for
enviable the hazards of as their considered opinion that a seriously burnt child will survivean operation of uncertain nature, providing a non-toxic agent, such as nitrous oxide, is used. I submit that the anaesthetist to the surgical team is best equipped to advise on the resultant of the four He is familiar with the variables mentioned above. hazards of anesthesia. His training has taught him to
to
time, with
of
an
anaesthesia, record
appreciate the effects on the patient of blood-loss and I surgical trauma associated with particular operations. I He knows, none better, the capabilities of his surgeon. I .
Pre-anoesthetic Medication is Atropine given to all patients in a dose proportional to the age of the patient. Children tolerate relatively large amounts of atropine and rarely show the uncomfortable-looking buccal and labial mucosa so characteristic of the atropinised adult. In the weeks immediately following a severe burn repeated anaesthetics are necessary to permit dressings and grafting operations. During this period too the basal metabolic rate rises rapidly and may remain
dry
t
raised for several months. This necessitates a nutritional intake well above normal requirements, and from the 2nd day onwards it is the custom, in this unit, for children to be put on a carefully planned diet. Recovery from anaesthesia must be rapid and uncomplicated if inter. ference with this dietetic regime is to be avoided. The anaesthetist should aim at having the child awake within minutes of completion of the dressing or operation, so that food may be given within an hour or two of his leaving the operating-theatre. For this reason pre. operative sedation is rarely used. This is contrary to the expressed opinion of psychiatrists, but experience has given little support to their anxious forebodings. Despite, or possibly because of, repeated anaesthetic experiences the child is surprisingly cooperative, appears to welcome the frequent visits to the theatre, and, with the anaesthetic technique detailed below, goes to sleep rapidly and
quietly. The occasional child who refused to become emotionally reconciled to visiting the theatre is given barbitone sodium by mouth (for dosage see table iv). This drug usually puts the patient to sleep and, because of the rate at which it is metabolised, recovery from its effects is fairly rapid. Should an operation be necessary in the period immediately following a burn, the child is controlled with diamorphine hydrochloride. At this time metabolic requirements are satisfied by parenteral administration. The haemoglobin level must be estimated preoperatively and any anaemia corrected. For grafting operations, during which the removal of skin and the excision of granulations will cause blood-loss, it is essential that a blood-transfusion should be given in the immediate preoperative period and again during the operation to replace any loss.
quinaÌ.
Anaesthetic
Technique
Once upon a time an inspired surgeon must have attributed the unfortunate death of one of his patients to his (the patient’s) failure to stand the anaesthetic." Since then this aphorism has been to the surgeon what enlargement of the thymus has been to the anaesthetist, and a surgeon, before subjecting a seriously ill patient to a lengthy and hazardous surgical operation, is often heard to ask the anaesthetist to examine the patient and report on his fitness to stand the anaesthetic." A review of the literature on anaesthesia, however. would almost certainly show that it is not the seriously ill patient who is likely to die from an anaesthetic but the robust healthy child who has been badly prepared. Furtber investigation would show that these deaths could invariably be attributed to some avoidable indiscretion on the part of the anaesthetist. The seriously ill patient appears to be unusually resistant to the hazards of anaesthesia and occasionally appears to be in better condition after the operation than he was before. This paradox is explained by the fact that the seriously ill are normally anaesthetised by experienced anaesthetists. Thev are less resistant to the effects of anaesthetic:. and satisfactory operating conditions may be induced "
"
115 ul maintained with relatively small amounts of anae.sftittit. In addition, modern anaesthetic techniques, far from being a danger to the patient, embrace the essentials of resuscitative therapy : rest, positioning, gen. blood-transfusions, &c. ruder anesthesia the patient is at complete rest ; :he airway is carefully maintained ;oxygen is given in high concentration and with positive pressure if necessary; rate and depth of breathing are maintained at optimal level : the pulse, colour, and blood-pressure are continuallyobserved and their significance interpreted ; where necessary to replace loss during bloud ,-neusive grafting operations, and the rate of the transfusion is regulated to satisfy the immediate needs of the patient. The seriously burnt child, to whom these restorative measures are so vitally important, shows benefit from this concentrated attention and, providing the surgical operanon is completed without unnecessary surgical trauma, appears in better clinical condition after the operation.
’ TABLE
agent
1) A rapid smooth induction free from coughing, struggling, which exhaust the child and stimulate the of obstructive secretions. (2) A high concentration of oxygen to satisfy the theranrutic and increased metabolic demands of the burnt child.
crying,
formation
3 Quiet breathing. (4) Minimal disturbance of metabolic and physiological" tumetions. The
surgical team has already spent many hours correct the upset caused by the burn. recovery to allow full and early expansion of the
attempting to (5) Rapid mgs
and
rapid resumption
of the dietetic
regime.
cyclopropane is well suited to meet these demands of the child. It may be given with high concentrations of and, being excreted unchanged, produces minimal of the body chemistry. Its central depressant ensures quiet breathing ; but most important is it is a gas. Absorbed and expelled through the lungs allows the anaesthetist to control not only its administon but also itsexcretion. This, combined with the . That cyclopropane is a powerful non-irritant agent a child from consciousness to respiramable of - arrest in 60-75 seconds, makes it the most flexible controllable of permitting rapid smooth tion. easy maintenance, and return to consciousness leavingthe operating-table. Feeding may be med 2-3 hours later. of Administration dopropane is administered with circle absorption the very young (aged less than 3 years), with a
taking
’
agents,
’
absorption.
DIMENSIONS
OF
MAGILL
,
It is impossible to dogmatise on the best anaesthetic agent for a burnt child. Indeed the flood of literature emanating from different centres and extolling the virtues of particular drugs for similar operations must lie very confusing to the casual anaesthetist and neutral observer. The truth is that the patient’s safety does not depend on the pharmacology of an anaesthetic drug so much as on the skill and experience of the anaesthetist administering it, combined with careful preparation and the meticulous application of whatever anaesthetic technique. is decided on. Anæthetic drugs are used essentially to provide satisfactory operating conditions, which, in similar operations, vary with individual surgeons. One may be able to work competently with a lightly anaesthetised patient where another would require, and demand, the curarised, pulseless, apnoeic, anthropomorphous mass popularised by the modern anaesthetist. Fortunately, in burns, the requirements of the surgeon are few. All he asks is a quiet patient and access to the burnt areas. It is possible, therefore, for the anaesthetist ti, concentrate on the demands of the child. These are as follows: - tnd
TUBES :
ORAL TUBES
is given
Anasthetic
V—ENDOTRACHEAL
Rapid induction to surgical anaesthesia is achieved after five or six breaths (30-40 seconds) by giving high concentrations of cyclopropane, the proportion of cyclopropane to oxygen being 3 to 1, and an2esthesia is maintained with a flow-rate of cyclopropane : oxygen 1 : 3 (50-100 c.cm. of cyclopropane : 300 c.cm. of oxygen). When the dressing is applied, the cyclopropane is turned off, and after one or two breaths of oxygen the mask is removed. Endotracheal intubation is used as an aid to the administration of cyclopropane in the following conditions : (1) Burns involving the face, head, and neck, if the surgeon is to have reasonable access to the parts. (2) Burns involving the dorsal surfaces, when positioning the child makes it difficult to maintain a clear airway. (3) Any child in whom respiratory embarrassment, even though minor, persists and cannot be relieved by either manipulation or the use of an oral airway. -
-
It has been suggested that the introduction of an endotracheal tube narrows the already narrow trachea of a child to a degree which itself causes respiratory embarrassment. This premise stimulated the corollary that the largest possible tube should be used and has led anaesthetists to screwing " into the trachea uncomfortably large lubricated tubes. I believe, despite assertions to the contrary, that it is the maintained pressure from such tubes that initiates the formation of membranes and post-anæsthetic laryngeal oedema reported recently. The tube sizes detailed in table v are proportionate to the size of the child ; they ensure an undisturbed airway and lie comfortably within the larynx. With such tubes these dangerous complications do not develop. Gentle handling is necessary in introducing the tube, particularly in the ill-nourished child with infection of the oropharynx ; but, provided the tube is introduced atraumatically, I have not found that these factors predispose to laryngeal oedema. It is unnecessary to lubricate the tube. Even although atropine has been given, the slimy moistness of the child’s laryngeal mucosa allows it to slip easily and atraumatically into the larynx. In children aged less than 8 years the vocal cords appear to mould themselves round the tube, and an airtight fit is obtained without a pharyngeal pack. This anaesthetic technique has been used routinely during the past eight years to anaesthetise children with burnt areas ranging from a slight extent to 60-70% of the body-surface. The results have been most satisfactory. The only complication during administration has been an occasional bronchospasm, which may be dangerous if not recognised early and rapidly relieved by the application of steady manual pressure to the rebreathing bag filled with oxygen. Cardiac irregularities associated with the use of cyclopropane in adults are rarely observed, and there have been no cases of postoperative atelectasis. "
I wish to thank Mr. A. B. Wallace, F.R.C.S.E., for encouragement and help in writing this article. REFERENCES
Barclay,
T.
L., Wallace, A. B. (1954) Lancet, i,
98.
Learmonth, J. R. (1940) In War-time Nurse. Edited by J. M. Mackintosh. Edinburgh; chapter III.